1. Field of the Invention
The present invention relates to a process for converting the mineral-containing residue resulting from coal liquefaction processes into hydraulic cement.
2. Brief Description of the Prior Art
Processes which convert coal or other carbonaceous materials to liquid products or to low mineral content meltable solids also produce large quantities of mineral-containing residue. One particular coal conversion process employs hydro-liquefaction of coal to produce both liquid and meltable solid products. The hydro-liquefaction process also produces a mineral-containing residue comprising from about 35 to 60 percent mineral matter with the balance being substantially high molecular weight aromatic compounds and carbon. The mineral matter includes kaolinite, calcite, gypsum, pyrrhotite and the like.
Presently, it is anticipated that the residue resulting from coal liquefaction processes will be employed as feed, either alone or in admixture with untreated coal, to gasifiers wherein hydrogen is produced. The hydrogen will be used in the liquefaction processes to improve the quality of the products. Generally, gasifiers are designed to handle feeds containing less than 35 percent mineral matter. When the residue from a hydro-liquefaction process containing in excess of 35 percent mineral matter is introduced into a gasifier certain problems arise. The gasifier can not be operated to produce the maximum quantities of hydrogen possible from the feed if mechanical operating problems are to be avoided. Thus, some valuable carbonaceous material is lost. The gasifier also produces a mineral ash which then must be disposed of in an ecologically acceptable manner.
It would be desirable to provide a process whereby the energy value of the mineral-containing residue from coal liquefaction processes can be recovered and the mineral content of the residue can be constructively and profitably utilized.